Improvement in photographic lenses



R. momassw.

improvement in Photographic-Lens.

Patented May 21,1872.

gumtur. 1

gum 9 UNITED STATES PATENT OFFICE.

RICHARD MORRISON, OF BROOKLYN, E. D., ASSIGNOR TO SOOVILL MANU- tion describing a new and Improved Lens, invented by RICHARD Mon- RISON, of Brooklyn, in the county of Kings and Stat of New York.

In my proved lens, which is designed for a wide-a1 'le view-lens, the front is composed of a plan convex lens of plate-glass, cemented to ano er piano-concave lens of flint-glass, of such c rves that will produce a combined lens sufli ently over-corrected for actinic rays to proper correct theback combination, which is chroma ic, and is composed of two lenses of plate-gla the first, or interior one, being a planocoi *ex, or double convex of the same focus as he second or exterior, which is a f nearly the same radiuses as the front co ination.

The dr wing is a sectional elevation of my improve View-lens.

A is t plano-convex lens, and B the planoconcave us of the front combination. 0 is the inter r plano-convex lens, and D the exterior m iscus lens of the back combination, having a pace between them at their axis. Instead a planoconvex lens O, I may use a double onvex lens in place of it. The focus from bacl lens is 4inches; diameter of lenses, 1. inch; stance from front to back lens, 1 inch. T ese dimensions may be varied, ac-

FAOTURING COMPANY, OF NEW YORK, N. Y.

IMPROVEMENT IN PHOTOGRAPHIC LENSES.

Specification forming part of Letters Patent No. 126,979, dated May 21,1872.

cording to the will of the constructor. The radius of the front lens A is 1.2 inch; the radius of lens B is 1.650 inch; combined focuses, 7 inches; radius of lens 0 is +12 inches; the radius of lens D, inches and +1.70 inch; focus of lens 0, 21 inches; meniscus, 22 inches; combined focuses, 11 inches. These will be varied as the focus of the front combination is varied.

The combining the meniscus lens D with lens (3 permits the use of lenses of shorter focuses with less spherical aberration than can be used with either a meniscus or convex lens separately. It also permits the use of larger openings in the diaphragm, thereby working in less time, with a wider angle.

Having thus described my invention, I claim as new and desire to secure by Letters Patent In a wide-angle view-lens, a meniscus lens placed behind a convex lens, so as to inclose an air meniscus between them, substantially as specified.

The above specification of my invention signed by me this 28th day of February, 1872.

RICHARD MORRISON.

Witnesses:

GEO. W. MABEE, T. B. MOSHER. 

